The design of this tool is helpful to any artist due to the knob being knurled and is convenient handling at 45°/90° and 30°/60°. the Alvin hardened steel triangle is made of indestructible nickel steel that was designed for cutting and measuring. This tool offers standard angels that can be drawn or cut. Alvin is one of the top sources for drafting supplies due to the quality of the products that are designed. Alvin continues to create exclusively designed fine art, hobby, and craft supplies. The Alvin Triangle Ni/Steel 45/90 Deg 15I receives five out of five stars. The Alvin Triangle is light weight and easy to handle and very durable. Alvin stands behind their products.